thiourea and Hypothyroidism

Wild-type medaka are known to have remarkable capabilities of fin, or epimorphic, regeneration. However, a hypothyroid mutant, kamaitachi (kmi), frequently suffers from injury in fins, suggesting an important role of thyroid hormone in fin regeneration. This led us to examine the relationship between thyroid hormone and fin regeneration using medaka as a model. For this, we first set up a medaka experimental system in which the rate of regeneration was statistically analyzed after caudal fin amputation under normal and hypothyroid conditions. As expected, the regeneration of amputated caudal fins was delayed in hypothyroid kmi -/- mutants. We then examined wild-type medaka with thiourea-induced hypothyroidism to evaluate the requirement of thyroid hormone during epimorphic fin regeneration. The results demonstrate that the growth rate of regenerates was much reduced in severely hypothyroid medaka throughout the regeneration period. This reduction in regenerative rate was recovered by exogenous administration of L-thyroxine. The present study is thus the first to report the direct involvement of thyroid hormone in teleost fin regeneration, and provides a basic framework for future molecular and genetic analyses.

Topics: Animals; Antibodies; Antithyroid Agents; Extremities; Female; Fish Diseases; Hypothyroidism; Male; Models, Animal; Oryzias; Radioimmunoassay; Regeneration; Thiourea; Thyroid Hormones; Thyroxine; Time Factors

Investigate the effects of systemic hypothyroidism upon the differentiated, growing, and regenerating retina of postmetamorphic winter flounder, a vertebrate that experiences a thyroid hormone (TH) induced metamorphosis during development.. A loss-of-signal strategy was utilized in which TH signaling was disrupted by inhibiting TH synthesis. Induced hypothyroidism was confirmed by radioimmunoassay. Reverse transcriptase PCR (RT-PCR), real-time quantitative PCR (qPCR), molecular cloning, non-isotopic in situ hybridization, western blot analysis, and indirect immunohistochemistry techniques were performed to analyze retinal thyroid hormone receptors (TR), photoreceptor production, and the phenotypic repertoire of differentiated retinal cells as a function of TH signaling status.. Molecular bases for TH signaling were supported by retinal expression of TH receptors alpha and beta. TH-dependent transcriptional regulation of TRalpha but not TRbeta was indicated, with induced hypothyroidism producing an increase in TRalpha expression. Evidence for post-transcriptional regulation of retinal TRalpha was observed. The repertoire of inner retinal cell types in premetamorphic fish (a naturally low TH condition) matched that observed in the central retinas of both normal postmetamorphic fish (a naturally elevated TH condition) and postmetamorphic fish rendered hypothyroidic. In differentiated postmetamorphic retina there was no evidence for significant differences in opsin expression between normal and hypothyroidic animals. Induced hypothyroidism did, however, significantly affect the types of photoreceptors that were produced in postmetamorphic retina: as a hypothyroidic postmetamorphic retina grew or regenerated following injury, the phenotypic repertoire of newly-produced photoreceptors matched that observed for premetamorphic retina, in which rods, SWS2-expressing "blue" cones, and LWS-expressing "red" cones are absent, and only the RH2-expressing "green" cone type is present. The effects of induced hypothyroidism upon photoreceptor specification (manifestation of the rod lineage) and differentiation (expression of a particular opsin by specified cones) were apparently reversible.. The results suggest a TH-dependent regulation of retinal TRalpha, a lack of TH-dependent regulation of the phenotypic identity of differentiated retinal cells, and the operation of similar cytogenic mechanisms during retinal growth and regeneration. The principal conclusion is that TH signaling significantly affects, in a targeted manner, the production of both rod and cone photoreceptors during retinal growth and regeneration.

Topics: Animals; Cell Differentiation; Cell Division; Flounder; Hypothyroidism; Metamorphosis, Biological; Phenotype; Photoreceptor Cells, Vertebrate; Regeneration; Retina; Signal Transduction; Thiourea; Thyroid Hormone Receptors alpha; Tissue Distribution; Triiodothyronine

An interval timing mechanism in the brain governs reproduction in seasonally breeding mammals by triggering refractoriness to inhibitory short photoperiods during midwinter. The neural mechanisms responsible for the timing and induction of photorefractoriness by this seasonal clock are unknown. Using cDNA microarrays and RT-PCR, we identified a class of genes encoding thyroxine (T4)-binding proteins (transthyretin, T4-binding globulin, albumin) whose expression is associated with reproductive refractoriness to short day lengths. Down-regulation of these genes was associated with reduced hypothalamic T4 uptake, which was reversed by long-day photoperiod treatments that restored responsiveness to short days. Circulating T4 concentrations did not vary with states of photoresponsiveness in euthyroid hamsters, but blockade of thyroid function accelerated the onset of photorefractoriness to short days. These data link changes in gene expression in the hypothalamus to the functional output of a seasonal clock. Reproductive inhibition in short days depends on T4 only late in the nonbreeding season. Down-regulation of genes encoding T4-binding proteins in the hypothalamus during this interval may restrict access of a static T4 signal to hypothalamic target tissues that regulate reproduction, thereby timing annual transitions in reproductive function. Hypothalamic autoregulation of T4 influx may constitute a critical cellular process involved in the generation and expression of seasonal reproductive rhythms and suggests a previously undescribed mechanism by which neural targets gain access to peripheral hormones.

Topics: Albumins; Animals; Biological Clocks; Cricetinae; Gene Expression Profiling; Gene Expression Regulation; Hypothalamo-Hypophyseal System; Hypothalamus; Hypothyroidism; Male; Nerve Tissue Proteins; Oligonucleotide Array Sequence Analysis; Organ Size; Phodopus; Photoperiod; Prealbumin; Reproduction; Reverse Transcriptase Polymerase Chain Reaction; Seasons; Testis; Thiourea; Thyroid Gland; Thyroxine; Thyroxine-Binding Proteins

Secondary iodine deficiency was experimentally produced in growing male lambs by oral administration of 50 mg/kg bodyweight of Thiourea daily for 3.5 months. At the end of the experiment the animals became weak, emaciated, anaemic, significantly reduced in body weight with facial oedema and alopecia at thigh, legs and abdomen. The clinical analysis showed significant reduction in erythrocyte and leucocyte numbers and in levels of triiodothyronine and testosterone at the end of the experiment. The histopathological picture of the thyroid gland revealed hyperplasia of the follicle-lining epithelial cells which project into the lumen. The lumens of the follicles are devoid of colloid. The testes showed ill-developed small, empty seminiferous tubulcs. In the liver, the hepatocytes showed degeneration and vacuolation with proliferation of Kupffer cells, which contain haemosiderin pigment. The kidney showed glomerular lipidosis with accumulation of haemosiderin pigment in the cytoplasm of the renal tubules. Hyperkeratosis of the epidermis associated with excessive keratin formation within the hair follicles was detected. In conclusion, deficiency of iodine causes hypothyroidism which leads to retardation of growth, reduced wool production and interferes with sexual maturity of growing male lambs.

Topics: Animals; Animals, Newborn; Disease Models, Animal; Hypothyroidism; Iodine; Male; Sheep; Sheep Diseases; Thiourea

We have shown earlier that the association of v-myc and v-erbA (MAHEVA construct) is responsible for the appearance of a specific phenotype in chick embryos inoculated at E3. This phenotype comprises rapidly growing heart rhabdomyomas (induced by v-myc alone) and within these tumors secondarily appearing cartilage nodules (Bachnou et al., Oncogene 6: 1041-1047, 1991). Here we report that v-erbA can be replaced by thyroid deficiency. When decapitated embryos were inoculated with virus MC29 (v-myc alone) or when v-myc inoculated embryos were treated with thiourea, 100% of the embryos reaching E17 to E19 displayed tumoral hearts bearing cartilage nodules. We thus report in vivo evidence that v-erbA acts by antagonizing the effects of thyroid hormones. Remarkably, thyroid deficiency rendered embryos more sensitive to the effect of v-myc, since 100% developed heart rhabdomyomas and cartilage nodules, versus about 70% affected when either v-myc or MAHEVA were inoculated. Thyroid deficiency did not alter the species-specific character of transdifferentiation, since only chick but not quail embryos developed cartilage nodules after thyroidectomy or MAHEVA infection.

Topics: Animals; Calcification, Physiologic; Cartilage; Cell Differentiation; Chick Embryo; Embryo, Nonmammalian; Heart Neoplasms; Hypothyroidism; Myocardium; Oncogene Protein p55(v-myc); Oncogene Proteins v-erbA; Phenotype; Quail; Rhabdomyosarcoma; Thiourea

The effect of hypothyroidism induced by 6-propyl-2-thiouracil (PTU) or thiourea (TU) on the development of the reproductive system in male and female neonatal ICR mice was investigated. PTU or TU was injected subcutaneously into experimental animals from postnatal day 1 (PD1) onward. The histological changes of the reproductive organs, formation of ovarian follicles, and spermatogenesis were examined on PD 14, 21, and 28, and the fertility of the hypothyroid mice in adulthood was followed. It was found that PTU or TU treatment did not produce an effect on the histology of the neonatal uterus and oviduct. In contrast, the drugs induced a decrease in the number of primordial follicles, multilaminar follicles, and Graafian follicles in the ovary. The number of follicles with degenerated follicular cells was increased. In the testis both PTU and TU treatments brought about a decrease in the number of seminiferous tubules with developing spermatids although the mean diameter of seminiferous tubules and the histology of the testis, epididymis, seminal vesicle, and coagulating gland was unaffected. The mating between hypothyroid females and euthyroid males and that between hypothyroid males and euthyroid females were normal with regard to the pregnancy rate, litter size, and sex ratio of offspring. The somatic growth of the resulting offspring was normal. It is concluded that the retarding effect on ovarian and testicular development in mice during neonatal period was not serious enough to adversely affect reproduction in the hypothyroid animals.

Topics: Animals; Female; Fertility; Hypothyroidism; Male; Mice; Mice, Inbred ICR; Ovarian Follicle; Ovary; Pregnancy; Propylthiouracil; Spermatogenesis; Testis; Thiourea

To accurately evaluate thyroid disorders in pregnancy, the physician must understand the physiologic changes that occur both in thyroid gland size and in thyroid function tests. The effect of thyrotoxicosis on pregnancy outcome largely depends on whether metabolic control is achieved. Women who become euthyroid on treatment usually can expect satisfactory outcomes. Propylthiouracil is considered to be the drug of choice for treating thyrotoxicosis during pregnancy. Because of the significant risk of hypothyroidism and obvious goiter in the infant, the use of iodide should be reserved for severe disease, such as thyroid storm or heart failure. Thyrotoxic infants may need antithyroid treatment until TSAbs are metabolized. Since overt hypothyroidism is often associated with infertility, it is uncommon in pregnancy. Hypothyroid women who do become pregnant, however, have an increased risk of low-birth-weight or stillborn infants. These women may require a greater dosage of thyroid hormone during pregnancy. The effects of subclinical hypothyroidism are not well defined. Accordingly, the need for treatment hinges on the woman's clinical history. Infants of hypothyroid mothers usually show no evidence of thyroid dysfunction, but those who are hypothyroid should receive prompt thyroid replacement therapy. To minimize the sequelae of congenital hypothyroidism, mass screening of infants and prompt treatment of those affected is recommended. During pregnancy, thyroid nodules should be evaluated by ultrasound and fine-needle aspiration or tissue biopsy. Radioiodine scanning should be avoided during pregnancy. If thyroid cancer is diagnosed, pregnancy should not delay treatment. Because postpartum thyroid dysfunction is fairly common yet difficult to detect, physicians and patients should be aware of the symptoms and risk factors.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adult; Female; Humans; Hyperthyroidism; Hypothyroidism; Infant, Newborn; Postpartum Period; Pregnancy; Pregnancy Complications; Pregnancy Outcome; Thiourea; Thyroid Crisis; Thyroid Diseases; Thyrotoxicosis

Female Syrian hamsters maintained on a 14 h light, 10 h dark photoperiod were injected once daily (1-2 h before lights out) with melatonin (25 micrograms), alone or in combination with thiourea, or with thiourea plus thyroxine. Serum levels of the somatomedin, Insulin-like growth factor-I (IGF-I), were significantly reduced by thiourea as well as by melatonin administration. These data suggest that in the female hamster melatonin-induced reduction of circulating IGF-I depends largely on a reduction in circulating levels of thyroid hormones. However, melatonin-induced changes in secretion of thyroid hormones, gonadal hormones, and hypothalamic hormones could contribute to decreased growth hormone (GH)-stimulated somatomedin secretion.

Topics: Animals; Cricetinae; Darkness; Disease Models, Animal; Drug Combinations; Female; Growth Hormone; Hypothyroidism; Insulin-Like Growth Factor I; Light; Melatonin; Mesocricetus; Radioimmunoassay; Somatomedins; Thiourea; Thyroxine; Triiodothyronine

The proliferation of Schwann cells in the sciatic nerve of chick was studied from day 11 to day 27 of development in control and thyroid-deficient embryos. Hypothyroidism was induced by tetramethylthiourea injection on days 8 and 19 of incubation. The parameters of the cell cycle were determined using autoradiographs (tritiated thymidine) and by image analysis of Feulgen-stained nuclear smears. The duration of the cell cycle was lengthened and the growth fraction was reduced in hypothyroid animals, at 11 and 15 days of incubation. At later stages (days 21 and 27), these parameters were not significantly different from the controls as if the sensitivity of Schwann cells to thyroid hormones was scheduled to occur during a limited period of development. The total number of axons was the same in control and hypothyroid animals suggesting that the slowing down of Schwann cell proliferation is not a consequence of neuronal cell death. The consequence of that slowing down is a delay in the isolation of promyelin axons and a reduction in the proportion of myelinated axons at all the stages studied.

Topics: Animals; Autoradiography; Cell Count; Cell Division; Chick Embryo; Embryonic and Fetal Development; Hypothyroidism; Schwann Cells; Sciatic Nerve; Thiourea; Thyroxine

Since melatonin injections administered near the end of the daily photoperiod influence both gonadal and thyroid hormones in the female hamster, the present study was designed to compare the effects of melatonin and hypothyroidism on the reproductive system and to determine whether thyroid status influenced the action of melatonin on the regulation of the hormones of reproduction. The effects of daily melatonin injections were determined in control hamsters, in hamsters rendered hypothyroid with thiourea, and in hypothyroid hamsters receiving thyroxin (T4) hormone replacement. As previously reported, melatonin injections disrupted estrous cyclicity, disrupted the normal pattern of gonadotropin secretion, and resulted in atrophy of the uterus and vagina. These changes coincided with depressed serum and pituitary prolactin (PRL), and depressed levels of estradiol. The effects of melatonin on uterus, vagina, ovary, and on gonadotropin levels were not prevented by T4 replacement, with the exception of a melatonin-induced increase in serum follicle-stimulating hormone (FSH). This suggested that the cessation of estrous cyclicity was not primarily a result of thyroid deficiency. Hypothyroidism, however, like melatonin, resulted in a reduced number of developing and mature follicles and corpora lutea in the ovaries, and in reduced uterine weight. It also produced follicular atresia, reduced the circulating levels of estradiol, and resulted in reduced incidence of estrus smears. T4 replacement, for 2 weeks, prevented the decline in mature follicles and corpora lutea, reduced the extent of follicular atresia, increased circulating levels of estradiol, and increased uterine weight. PRL and luteinizing hormone (LH) data also provided evidence for antagonistic effects of melatonin and T4 in female hamsters. These data raise the question whether melatonin-induced changes in circulating levels of T4 play a role in the seasonal cycles of reproductive competence in the female hamster.

Topics: Animals; Cricetinae; Estradiol; Female; Gonadotropins, Pituitary; Hypothyroidism; Luteinizing Hormone; Melatonin; Mesocricetus; Ovary; Pituitary Gland; Prolactin; Thiourea; Thyroid Hormones

The effects of daily evening melatonin injections on serum and pituitary levels of growth hormone (GH) and follicle stimulating hormone (FSH) were investigated in male Syrian hamsters receiving thiourea in the drinking water. Melatonin injections, by themselves, had no significant effect on serum or pituitary GH. Thiourea induced hypothyroidism reduced pituitary GH content but increased serum GH several fold. Daily thyroxin (T4) injections for 3 weeks partially restored pituitary GH content and reduced circulating GH to control values. Melatonin injections prevented T4 from reducing circulating GH levels to normal in hamsters receiving thiourea. As previously reported, FSH levels in serum and pituitary were reduced by melatonin. Thiourea-induced hypothyroidism prevented this effect. Daily T4 injections increased circulating FSH levels above control levels; melatonin injections prevented this increase in serum FSH. These observations show that melatonin and T4 have antagonistic actions on GH and FSH release from the pituitary. We conclude that melatonin influences the release of hypothalamic hormones regulating GH and FSH release from the pituitary. The effects of T4 on the sensitivity to melatonin injections could be accounted for by thyroid hormone regulation of pituitary receptors for hypothalamic hormones. An alternative explanation is that T4 regulates the concentration of melatonin receptors in the central nervous system.

Topics: Animals; Cricetinae; Follicle Stimulating Hormone; Growth Hormone; Hypothyroidism; Male; Melatonin; Mesocricetus; Pituitary Gland, Anterior; Thiourea; Thyroxine

A single injection of L-triiodothyronine (T3) in different doses (0.25, 0.5, 5, 20 and 50 micrograms/g) increased the hepatic mitochondrial cytochrome-linked alpha-glycerophosphate dehydrogenase (alpha-GPD) activity and mitochondrial protein content of Singi fish, as observed on the 3rd day. A non-linear dose-response relationship with respect to enzyme activity was observed with different doses of T3. A low dose of 0.1 micrograms of T3 per g failed to cause any change in alpha-GPD activity and mitochondrial protein content of the liver. The enhancement of alpha-GPD activity over the control level with a low and a high dose of T3, viz., 0.5 and 5 micrograms/g, was followed from the 1st to the 7th day, when it was found that enzyme activity reached the maximum level on the 3rd day and then gradually declined to the control value on the 7th day. The percentage increase in enzyme activity with 5 micrograms/g was higher than that with 0.5 microgram/g from the 2nd to 5th day. Compared to the control, these two doses of T3 caused an increase in alpha-GPD activity from the 1st to the 6th day. Cycloheximide inhibited the T3-induced increase in alpha-GPD activity, mitochondrial and total protein content of liver. Immersion of Singi fishes in thiourea-containing (1 mg/ml) medium for 30 days showed a fall in hepatic alpha-GPD activity in comparison to the euthyroid control. A single injection of T3 (0.5 microgram/g) to the hypothyroid fish recovered alpha-GPD activity to more than the euthyroid control level. An increase in mitochondrial protein content in the T3-injected hypothyroid fish has been observed. DNA content of the fish liver remained unchanged in every experimental condition. The results thus showed the significant responsiveness of the fish liver to thyroid hormone.

Topics: Animals; Cycloheximide; Dose-Response Relationship, Drug; Fishes; Glycerolphosphate Dehydrogenase; Hypothyroidism; Mitochondria, Liver; Reference Values; Thiourea; Triiodothyronine

A morphometric analysis of Purkinje cells in the developing cerebellar cortex of the chick was performed in normal animals and embryos made hypothyroid by one or two spaced injections of tetramethylthiourea. Profiles of 162 Purkinje cells, from Golgi-Cox treated sections were analysed. Soma area, perimeter and circularity index, cumulative length of the dendrites and number of dendritic bifurcations were studied. The results showed significant differences between control and hypothyroid animals. There were no important differences between birds rendered transiently hypothyroid with a single injection and those made chronically hypothyroid with dual injections. This confirms that the Purkinje cell is very dependent on thyroid hormone especially during the early phases of its morphogenesis. The development of the Purkinje cell was the most affected process of cerebellar cortex maturation in the thyroid-deficient chick. The dendritic arborization was particularly hypoplastic. Moreover, a dynamic balance appeared to exist between the development of the dendritic arborization and that of the perikaryon.

Topics: Animals; Cell Count; Cerebellar Cortex; Chick Embryo; Chickens; Dendrites; Hypothyroidism; Purkinje Cells; Thiourea; Thyroid Hormones

Male Syrian hamsters were kept under either 14 h light/10 h dark (lights on at 06.30 h) or 2 h light/22 h dark (lights on at 14.30 h) photoperiods. Groups of hamsters under each photoperiod were rendered hypothyroid by addition of 0.4% thiourea to the drinking water. These hamsters received, in addition, either a daily evening injection of saline or a daily injection of 25 micrograms melatonin in saline. Groups of intact controls and pinealectomized control hamsters were also maintained under the two photoperiodic conditions. After 10 weeks under the different conditions the hamsters were killed by decapitation, and serum samples assayed for thyroxin, thyroid-stimulating hormone (TSH), and prolactin (PRL). Pituitary extracts were assayed for TSH and PRL. Hypothyroidism in hamsters receiving thiourea was confirmed by radio-immunoassay data showing low serum thyroxin and greatly elevated serum TSH concentrations. Melatonin injections resulted in significant depression of serum TSH in thiourea-treated hamsters under short photoperiod compared to saline-injected controls. Both melatonin injections and short photoperiod resulted in a significant reduction of pituitary TSH in hamsters on thiourea compared to values obtained from similarly treated animals under the 14 h light/10 h dark photoperiod. Hypothalamic concentrations of thyrotropin-releasing hormone (TRH) were significantly elevated by melatonin injections and by short photoperiodic conditions, but not by thiourea administration. The short photoperiod resulted in testicular involution which was completely reversed by pinealectomy and partially reversed (to 53% of controls) by thiourea treatment. Involution of gonads was complete in thiourea-treated animals under short photoperiod, if they received melatonin injections.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Cricetinae; Hypothalamo-Hypophyseal System; Hypothyroidism; Male; Melatonin; Mesocricetus; Pituitary Gland; Prolactin; Thiourea; Thyrotropin

The effects of daily evening melatonin injections on plasma and pituitary levels of TSH, LH, and PRL in hypothyroid hamsters maintained under a 14-h light, 10-h dark photoperiod were investigated. Circulating levels of thyroid hormones were monitored, and testicular weights were recorded. Thiourea-induced increases in serum and pituitary TSH were significantly reduced by melatonin injections. Control hamsters, not receiving thiourea, responded to daily evening melatonin injections with a decrease in serum T4. Serum T3 levels were decreased by thiourea and increased by T4 replacement. The pituitary PRL content was significantly reduced below control values in hamsters receiving melatonin injections; the sensitivity to melatonin was inhibited by thiourea and restored by T4 replacement. T4 replacement injections were associated with a significant decrease in serum PRL and a significant increase in serum LH. Melatonin-induced testicular involution was attenuated by thiourea administration; this attenuation was reversed by T4 replacement. Similarly, a melatonin-induced decrease in serum LH was prevented by thiourea administration and restored by T4 replacement. The data suggest that melatonin injections increase the sensitivity of the pituitary to T4/T3 feedback inhibition of TSH. Furthermore, these data show that thyroid status may influence melatonin-induced changes in release of PRL and LH from the hamster pituitary. The data showing an interaction of thyroid hormones in the control of testicular size are interpreted as evidence that thyroid hormones play a major role in the mechanism regulating gonadal cycles in the hamster.

Topics: Animals; Cricetinae; Hypothyroidism; Light; Luteinizing Hormone; Male; Melatonin; Mesocricetus; Pituitary Gland; Prolactin; Thiourea; Thyrotropin; Thyroxine; Time Factors

The activity of pyruvate kinase (PK), an enzyme playing a key role in glycolysis, was studied in the lung of Wistar R/A rats in the prenatal, postnatal and adult periods of life. The highest level was measured on the 20th gestational day, a value nearly double the adult mean. In order to elicit fetal hypothyroidism, pregnant rats were treated with 0.1% thiourea solution from the 14th day of gestation up to delivery. The animals were killed on the 21st or 22nd gestational day or on the 2nd postnatal day. A significant increase in PK activity was seen in the treated animals as compared to the control group, while the activity of phosphatidic acid phosphatase (PAPase) remained unchanged. Fetal hyperthyroidism was induced by intravenous injections of TRH to the pregnant mother rat. This resulted in an increase of PAPase and a decrease of PK activity as compared to the control group. The difference was statistically significant in all instances, the level of significance, however, depended on the time when treatment had been initiated.

Topics: Administration, Oral; Aging; Animals; Animals, Newborn; Female; Fetus; Hyperthyroidism; Hypothyroidism; Injections, Intravenous; Lung; Maternal-Fetal Exchange; Phosphatidate Phosphatase; Phosphoric Monoester Hydrolases; Pregnancy; Pyruvate Kinase; Rats; Rats, Inbred Strains; Thiourea; Thyroid Gland; Thyrotropin-Releasing Hormone

Topics: Animals; Axons; Chick Embryo; Chickens; Hypothyroidism; Myelin Sheath; Nervous System; Schwann Cells; Skin; Thiourea

Goats given thiourea had hypothyroidism in various degrees. There was reduction in weight gain and oedema of face and limbs. There was an increase in serum cholesterol which was highest in goats given the lowest dose of thiourea. Protein-bound iodine decreased sharply and there was an increase in plasma protein.

Topics: Animals; Female; Goats; Hypothyroidism; Male; Thiourea

The influence of thyroid deficiency and the administration of thyroxine on pituitary-testicular function were studied in male albino rats from weaning age (22 days old) up to 82 days of age. The results showed that the hyperthyroid state induced by a daily injection of 2.5 or 5 microng L-thyroxine resulted in acceleration of growth, a comparative increase in size and number of spermatogenic and interstitial cells, an increase in the STH cells, particularly at the earlier age (42 days old), and in a decrease in the number and size of TSH cells. Gonadotrophic FSH and LH and prolactin cells exhibited an increase in their granular content. The hypothyroid state induced by thyroidectomy or thiourea feeding, at the levels of 0.1 and 0.2% resulted in the depression of growth rate, destructive changes of the spermatogenic and interstitial cells and also in the lumen of the seminiferous tubules. A decrease in the STH, gonadotrophic FSH and LH and prolactin cells and hypertrophy of TSH cells accompanied by degranulation were also observed.

Topics: Age Factors; Animals; Body Weight; Growth; Hyperthyroidism; Hypothyroidism; Male; Pituitary Gland; Rats; Rats, Inbred Strains; Spermatogenesis; Testis; Thiourea; Thyroid Gland; Thyroidectomy; Thyroxine

Topics: Hyperthyroidism; Hypothyroidism; Iodine Radioisotopes; Lithium; Preoperative Care; Propranolol; Thiourea; Thyroxine

Topics: Animals; Ascorbic Acid; Blood Proteins; Histocytochemistry; Hypothyroidism; Kidney; Leucyl Aminopeptidase; Male; Rats; Stimulation, Chemical; Thiourea

Topics: Adrenergic beta-Antagonists; Antithyroid Agents; Carbimazole; Chemical Phenomena; Chemistry; Humans; Hyperthyroidism; Hypothyroidism; Imidazoles; Iodine Isotopes; Methimazole; Methylthiouracil; Myocardial Infarction; Perchlorates; Potassium; Potassium Iodide; Propranolol; Propylthiouracil; Psychotic Disorders; Thiourea; Thyroxine; Time Factors

Topics: Acid Phosphatase; Alcohols; Animals; Body Weight; Caseins; Cell Fractionation; Colon; Esterases; Esters; Hyperthyroidism; Hypothyroidism; Iodine; Iodoproteins; Liver; Lysosomes; Male; Oxidoreductases; Palmitic Acids; Rats; Spectrophotometry; Sulfatases; Thiourea; Thyroid Gland; Ultraviolet Rays; Vitamin A

Topics: Androgens; Animals; Hypothyroidism; Male; Rats; Testis; Thiourea

Topics: Animals; beta-Aminoethyl Isothiourea; Fishes; Guanidines; Hyperthyroidism; Hypothyroidism; Iodine Isotopes; Photomicrography; Radiation-Protective Agents; Sulfhydryl Compounds; Thiourea; Thyroid Gland; Thyroxine

Topics: Genetics, Medical; Goiter; Humans; Hyperthyroidism; Hypothyroidism; Japan; Nuclear Warfare; Phenylthiourea; Taste; Thiourea; Thyroid Neoplasms; Thyroiditis

Topics: Animals; Body Temperature Regulation; Cold Temperature; Fishes; Goiter; Hot Temperature; Hypothyroidism; Research; Temperature; Thiourea; Thyroid Gland; Thyroxine

Topics: Adrenal Glands; Animals; Hypothyroidism; Leadership; Rats; Testosterone Propionate; Thiourea

Topics: Animals; Coitus; Female; Guinea Pigs; Hypothyroidism; Maintenance; Male; Thiouracil; Thiourea; Thyroid Gland

Topics: Animals; Facial Bones; Hypothyroidism; Jaw Abnormalities; Propylthiouracil; Rats; Thiourea; Thyroid Gland

Topics: Animals; Estradiol; Estrogens; Female; Guinea Pigs; Hypothyroidism; Thiouracil; Thiourea; Thyroid Gland